Definition: In this task, you are given an input list A. You need to convert all the alphabets in the list with a number representing their position in the English alphabet. E.g., replace A by 1, B by 2, a by 1, b by 2, and so on.
Input: ['3863', '5057', 'u', 'D', 'T', '9815', 'k']

3863, 5057, 21, 4, 20, 9815, 11